Adjustable crank for bicycles or velocipedes



No. 625,986. Patented May 30, I899. F. a. PENNUCK.

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@We, 06 Mat PM W. a -W UNITED, STATES PATENT OFFICE.

FREDERICK G. PENNOCK, OF BRAINTREE, MASSACHUSETTS, ASSIGNOR OF- ONE-HALF TO IVILLIAM H. DOBLE, OF QUINCY, MASSACHUSETTS.

ADJUSTABLE CRANK FOR BICYCLES OR VELOCIPE D ES.

SPECIFICATION forming part of Letters Patent No. 625,986, dated May 30, 1899.

Application filed. January 8, 1898. Serial No. 666,008. .No model.)

To all whom it may concern: shaft, which is here represented as made in Beit known that I,FREDERIOK G.PENNOOK, two sections, one section on each cranka citizen of the United States, residing at holder, and the two sections having respec- Braintree, in the county of Norfolk and State tively a tongue and a groove which fit toof Massachusetts, have invented certain new gether. The groove 6 is shown in Fig. 3; but and useful Improvements in Adjustable none of the drawings show the section having Cranks for Bicycles or Velocipedes, of which the tongue, which, however, will be well unthe following, taken in connection with the .derstood and does not form a part of my inaccompanying drawings, is a specification. vention.

10 The object of my invention is to produce a My invention applies equally well where crank for bicycles and the like which can be the crank is composed of a single piece. The adjusted by simple foot-pressure to give a crank 7 is formed with a shank 8, squarelonger or shorter throw, as desired, without sided up as far as desired, according to the dismounting or stopping the wheel. There amount of extensibility required. Any other 15 have been various kinds of attachments made shape except circular would serve the purfor varying the throw of the crank, but none, pose, it being made of a shape not to turn so far as I am aware, have been so constructin its holder. The shank fits in a hollow ed that by a downward pressure of the foot holder 9,which hasarec-tangular hole through on the pedal without dismounting the crank it lengthwise and is cast with or secured to 20 can be either lengthened or shortened, as dethe crank-shaft 5. If the crank-shaft emsired, and retained in its adjusted position. ployed be a single piece, then the holder 9 Some have been made which vary the length should be detachable. The shank 8 fills the of throw at each up and down stroke, but do hole, except a space on one side to allow room not remain in an adjusted position throughfor the flat spring 10. Ashoulder 11 is formed 25 out the full stroke or for any length of time on the crank at the top of the shank, and a desired. cap 12 has a screw 13, which is screwed into My invention consists in a crank arm and a threaded hole in the lower end of the shank. holder with looking attachment, whereby the The cap projects over the side of the shank, length of throw of the crank-arm may be vaso that it forms a rest for the end of the spring 0 ried and the crank secured in its adjusted po- 10. This spring 10 is flat and bow-shaped, 8o

sition by a downward pressure of the foot and when straightened out fills the space bewithout dismounting, as will be clearly set tween the shoulder 11 and the cap 12. forth in the specification. In mounting the crank the shank 8 and In the drawings, Figure 1 is a front elevaspring 10 are inserted in the holder 9 while 5 tion showing a crank-hanger with my imthe cap 12 is detached. The cap then is seproved crank-holders and cranks attached, cured to the end of the shank and prevents the cranks being in their shortened position. displacement of the crank until the cap is un-. Fig. 2 is a side elevation showing a crankscrewed again. Fig. 2 represents the crank holder and one of the cranks as it appears in in its most extended position. The tension 0 its extended position. Fig. 3 is a cross-secof the lower part of the spring is sufficient to tion on line 3 3 of Fig. 2. Fig. 4 is a side elekeep the crank in the extended position unvation of one of the crank-arms detached and der the ordinary pressure to which the pedals showing the locking-spring in position. Fig. are subjected while riding.

5 is a perspective of the locking-spring de- Wheneveritis desired to shorten the crank,

45 tached. Fig. 6 shows the head with screwthe rider will exert a little extra downward stem, which screws into the-end of the crank pressure with his foot when the crank is in to form the abutment for'one end of the lockits upper vertical position, as shown in Fig. ing-spring. 2, taking first one and then the other as it 1 is the crank-hanger; 2 and 3, the seat and comes around, and they will be shortened up, 50 frame posts; 4, the sprocket, and 5 the crankas in Fig. 1. The shoulder 11 is wider than I00 to merely form an abutment for the end of the spring, so that it also serves as a stop to prevent the crank from being pushed in too far. \Vhen the cranks are in the shortened position, as in Fig. 1, and the rider comes to a hill or for any reason desires to have a longer throw of the crank, he will press down on the pedal when in its lower vertical position with sufficient extra pressure to overcome the tension of the spring, and the crank will be pushed out to its lengthened position.

The cap 12 serves as a stop to prevent the crank from being pulled out of the holder when the crank has reached the limit of its proper length of throw.

What I claim is 1. In a bicycle or veloeipede, in combination with a crank-shaft, a holder fixed to the crank-shaft, a crank adjustable in said holder and unitary throughout its length, a tension device which holds the crank at any position to which it is adjusted, the crank being adjustable to increase and decrease the lengths of throw solely by additional pressure on the pedal but varying only when such pressure is exerted and having a length at least as great as the longest radius of rotation, substantially as described.

2. In combination with a crank-shaft, a tubular crank-holder, a crank having a shank which extends through said holder lengthwise and is adjustable therein, said crank being unitary throughout its length and having a length at least as great as the longest radius of rotation, a pedal connected to said crank, a binding-spring within the holder and bearing against the crank-shank which by its tension alone holds the crank at any length to which it is adjusted, the crank being adjusted by a pressure on the pedal exerted only in a direction parallel with the axis of the crank, substantially as described.

3. In combination with a bicycle crankshaft, a holder slotted lengthwise thereof radially to the crank-shaft, a crank having a shank which is mounted in said slot, aplatespring which fits in said slot and against the side of said shank, a detachable cap on the butt-end of the shank with projecting edge which forms a rest for one end of said spring, and a shoulder on the shank which forms a rest for the inner end of the said spring, whereby the crank will be held in its adjusted position by the tension of the spring, substantially as described.

at. In a bicycle or velocipede, in combina* tion with a crank-shaft, a crank-holder fixed to the crank-shaft, a crank in said holder unitary throughout its length and a pedal connected therewith, the crank having a length at least as great as the longest radius of rotation and being adjustable to different lengths of throw at the will of the rider by additional pressure on the pedal, and a stop which prevents the crank from becoming disconnected with the holder, substantially as described.

In testimony whereof I afiix my signature in presence of two witnesses.

FREDERICK G. PENNOCK.

lVitnesses:

WILLIAM A. COPELAND, EDITH J. ANDERSON. 

